Volitional Hamstring Force Production During Closed Kinetic Chain Lower Extremity Exercise in Supine Position: A Randomized Controlled Trial

Abstract

Purpose and hypothesis: The purpose of this study is to quantify and compare force production of the biceps femoris and semi-membranous muscles during the performance of supine, closed chain lower extremity strengthening exercises. Volitional force production and joint position were investigated during specified closed chain lower extremity activities including: supine hemi bridge, elevated hemi bridge and heel slide Hemi Bridge. Materials and methods:This study consisted of sixty participants recruited from various cohorts of the college student population via convenience sampling method. Subjects were randomized by lottery selection and evenly distributed to one of three exercise groups: supine hemi bridge (n=20), elevated hemi bridge (n=20) and heel slide hemi bridge (n=20). All exercises were performed three times upon the subject's dominant lower extremity. In each group, force production of the biceps femoris and semi-membranous muscles were measured using a wireless electromyogram (EMG) (2016 DELSYS Trigno™ Sensor System) unit with surface electrodes. Participant exercise performance was also monitored during each exercise by use of a digital postural assessment tool (2016 Postureco™ Posture Screen Mobile).Results: Total 50 participants (23 males and 27 females) completed the study. Semi-membranous force productions were 3.39, 3.85 and 3.72 mV on the supine, elevated and heel slide hemi bridge exercises respectively. Biceps femoris force productions were 5.79, 4.50 and 4.75 mV on the supine, elevated and heel slide hemi bridge exercises respectively The results of the one-way ANOVA for semimembranous and biceps femoris force production were p=0.890 and p=0.266 respectively, indicating no significant differences between the three exercises. Conclusion:The supine hemi bridge, elevated hemi bridge and heel slide hemibridge were equally effective in activating the semi-membranous and biceps femoris during supine, closed chain lower extremity strengthening exercises. However, variances among EMG data indicate distinct clinical implications on exercise prescription.